We use the kitchen timer and set it for 10 minutes. Every time it goes off we check the headings and surroundings very thoroughly. We also check the engine
if it's running. The timer depends on where you are traveling. Also, we found a short ring to be better and less likely to wake the off watch than a long ring.
I use a CD player with headphones to keep myself up and active during the later watches. I tend toward seasickness, so reading is not good for me. I also do stretches and knee bends while holding the pedestal
We always have granola bars for watches - easy to grab and eat. As well as making hot tea or chocolate, before we come on duty. Some folks prefer protein snacks, and hardboiled eggs are great for this. Others must have cookies. Slices of salami are easy, apples are healthy.
We keep red-lensed, pen-size, flashlights in our pockets at all times. We trade
off on a watch for the on-watch crew. We try to bring out as much as we can when we take over, so as to keep movement below to a minimum. (This is for off-watch comfort.) Obviously, this is weather
Even in the summer it can be cool at night, expecially if you are tired, so be sure to have a jacket or sweater handy.
The shorter passages are the harder ones as you are not acclimated. The near coastal passages are difficult due to more things to be careful of.
Nap as much as you can, even if it's only 20 mins. I've found it easier to fall asleep if I try meditation - concentrating on my breathing.
Enjoy the passage, you will be someone new at the end. (I also find personal growth during these times.)